1. Field of the Invention
The present general inventive concept relates to transmission of data to a print head chip, and more particularly, to a data interfacing apparatus and method of a print head chip by which a number of signal traces and ground traces are reduced and signal distortion caused by signal transmission is reduced.
2. Description of the Related Art
It is very important to process signals and grounds of a system according to low-speed signals and high-speed signals.
FIG. 1 is a diagram of return paths formed by transmission of a low-speed signal between a driver and a head chip. Referring to FIG. 1, the return paths in dotted lines are formed on an inner layer or plane. At low speed the return paths are formed closer to a point of least resistance.
FIG. 2 is a diagram of return paths formed by transmission of a high-speed signal between a driver and a head chip. Referring to FIG. 2, the return paths in dotted lines are formed on an inner layer or plane. At high speed the return paths are formed closer to a trace of the high-speed signal. That is, at high speed the return paths are formed closer to a point of lowest inductance. In more detail, the return paths have a pattern of a mirror right below the trace of the high-speed signal and define a smallest loop area. However, if the return paths are not obtained between the driver and the head chip, the transmission of the high-speed signal causes signal distortion and noise.
FIG. 3 is a diagram of components used to transmit signals between a driver 10 and a head chip 30. Referring to FIG. 3, a reset signal Reset and two temperature sensing signals Temp1 and Temp2, which are low-speed signals, are transmitted to the head chip 30 from the driver 10. A clock signal CLK, a print data signal PData, and a load signal Load, which are high-speed signals, are transmitted to the head chip 30 from the driver 10. However, a return current path is formed between the clock signal CLK and a print data plus signal PData, which reduces possibility of the occurrence of signal distortion. However, a return current path is not formed between a print data minus signal PData, which is another high-speed signal, and the load signal Load, which increase possibility of the occurrence of signal distortion when the load signal Load is transmitted to the head chip 30 from the driver 10.
To prevent the occurrence of signal distortion, the return current path can be formed in all signal traces to transmit the high-speed signals such as the load signal Load, etc. However, this solution requires increasing the number of pins of the driver 10 and the number of cables 20 corresponding to signal traces and ground traces which inevitably increases costs and reduces transmission efficiency.